Piping unit for air conditioning device

ABSTRACT

A pipe unit ( 50 ) is provided for a refrigerant circuit which performs a vapor compression refrigeration cycle by circulating a refrigerant. The pipe unit ( 50 ) includes a pipe body ( 53 ) having a liquid pipe ( 51 ) through which a liquid refrigerant for the refrigerant circuit ( 40 ) flows and a gas pipe ( 52 ) through which a gaseous refrigerant for the refrigerant circuit ( 40 ) flows; and a heat insulator ( 54 ) covering each of the liquid pipe ( 51 ) and the gas pipe ( 52 ) separately. The liquid pipe ( 51 ) and the gas pipe ( 52 ), each of which is covered with the heat insulator ( 54 ), are fixed together to form a single piece. Such partial unitization of the refrigerant circuit allows for reduction in the number of days required for installation of an air conditioner.

TECHNICAL FIELD

The present invention relates to a pipe unit of an air conditioner, andmore particularly relates to a pipe unit of a refrigerant circuit.

BACKGROUND ART

Some conventional air conditioners are installed in buildings byconnecting a plurality of indoor units to a single outdoor unit asdisclosed by Patent Document 1. In the present circumstances, most ofthe installation process of such an air conditioner, including pipeconnection, is performed on site after the framework of the building isfinished.

CITATION LIST Patent Document

[Patent Document 1] Japanese Unexamined Patent Publication No.H07-280376

SUMMARY OF THE INVENTION Technical Problem

In the conventional installation process of the air conditioners,however, most of its piping work is done on site, and a refrigerantcircuit is not unitized in the present circumstances. Thus, it takesmany days to finish installing the conventional air conditioners, whichis a problem. Specifically, pipe installation and heat insulation workneed to be performed in confined space such as a roof space. Thus, ittakes a great number of skilled workers and long working hours to getsuch installation done, which is also a problem. For these reasons,there have been growing demands for unitization of the refrigerantcircuit.

In view of these problems, the present invention has been made to reducethe number of days required for the installation by partially unitizingthe refrigerant circuit.

Solution to the Problem

A first aspect of the invention is a pipe unit provided for arefrigerant circuit (40) which performs a vapor compressionrefrigeration cycle by circulating a refrigerant. According to the firstaspect of the invention, the pipe unit includes a pipe body (53) havinga liquid pipe (51) through which a liquid refrigerant for therefrigerant circuit (40) flows and a gas pipe (52) through which agaseous refrigerant for the refrigerant circuit (40) flows; and a heatinsulator (54) covering an outer periphery of the pipe body (53). Theliquid pipe (51) and the gas pipe (52) of the pipe body (53) are fixedtogether to form a single piece.

According to the first aspect of the invention, a refrigerant circuit(40) is partially unitized by fixing a liquid pipe (51) and a gas pipe(52) together to form a single piece. The fabrication of a pipe body(53) and the covering of the pipe body (53) with a heat insulator (54)can be performed in a factory. This allows for reduction in the numberof days required for installation of an air conditioner.

A second aspect of the invention is an embodiment of the first aspect ofthe invention. In the second aspect, the heat insulator (54) covers eachof the liquid pipe (51) and the gas pipe (52) separately, and the liquidpipe (51) and the gas pipe (52), each of which is covered with the heatinsulator (54), are fixed together to form a single piece.

According to the second aspect of the invention, the heat insulator (54)covers each of the liquid pipe (51) and the gas pipe (52) separately,and the liquid pipe (51) and the gas pipe (52), each covered with theheat insulator (54), are fixed together to form a single piece. Thisallows for simplification of fabrication work.

Advantages of the Invention

According to the present invention, the refrigerant circuit (40) ispartially unitized by fixing the liquid pipe (51) and the gas pipe (52)together to form a single piece. Thus, the pipe unit of the presentinvention can be fabricated in a factory. This reduces the number ofdays required for the installation of the air conditioner significantly.Specifically, the connecting work which has been carried out on site isreplaced with the work in the factory. This allows workers to get theirwork in a confined roof space and other time-consuming jobs done muchmore easily, thereby reducing the number of days required for theinstallation significantly.

In particular, the brazing process for connecting the pipe body (53) isperformed only in the factory. Thus, work using fire is restricted onlyto the factory, and no work using fire is performed on site any longer.This eliminates the occurrence of fire accidents on site. In addition,the brazing process performed in the factory reduces the number ofpositions where the fitting couplings (43) are used. This reduces thenumber of the expensive couplings (43) to use, which allows for cuttingdown the installation cost.

The pipe body (53) is covered with the heat insulator (54) in thefactory. This reduces significantly the need for covering the parts withthe heat insulators (54) on site. As a result, the accuracy of the heatinsulation work increases significantly, thereby preventing the moisturecondensation with reliability. In particular, the moisture condensationmay occur after a year or more has passed since the installation wasfinished. The pipe unit of the present invention is very effective atpreventing such moisture condensation.

According to the second aspect of the invention, the heat insulator (54)covers each of the liquid pipe (51) and the gas pipe (52) separately,and the liquid pipe (51) and the gas pipe (52), each covered with theheat insulator (54), are integrated to form a single piece. This allowsfor simplification of fabrication work.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a general configuration for an airconditioner.

FIG. 2 is an exploded perspective view showing a branch coupling unit asa first pipe unit.

FIG. 3 is an exploded perspective view showing a pipe body of the firstpipe unit.

FIG. 4 is a plan view showing the first pipe unit.

FIG. 5 is a perspective view showing a second pipe unit.

FIG. 6 is a plan view showing a coupling.

FIG. 7 is a plan view showing a band body of a suspending band.

FIG. 8 is a side view showing the band body of the suspending band.

FIG. 9 is a side view showing the suspending band in use.

FIG. 10 is a flow chart showing a procedure of installation of an airconditioner.

FIG. 11 is a flow chart showing a planning step of the air conditioner.

FIG. 12 is a plan view showing a design drawing of a building.

FIG. 13 is a plan view showing a piping drawing of the building.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will now be described in detailwith reference to the drawings.

As shown in FIG. 1, an air conditioner (10) of the present embodiment isan air-conditioner for buildings installed in, for example, a building(1) which is a construction, and is a so-called multiple air conditionerin which each single outdoor unit (20) is connected to a plurality ofindoor units (30).

The air conditioner (10) includes refrigerant systems (1A, 1B, 1C), eachof which includes a single outdoor unit (20) and a plurality of indoorunits (30) and is provided for an associated one of multiple differentfloors. For example, the air conditioner (10) includes three refrigerantsystems. The air conditioner (10) includes, in each of the refrigerantsystems (1A, 1B, 1C), a refrigerant circuit (40) which performs a vaporcompression refrigeration cycle by circulating a refrigerant between theoutdoor unit (20) and the indoor units (30).

The outdoor unit (20) is installed on the roof floor of the building(11), for example, and includes a casing that houses devices such as acompressor, an outdoor heat exchanger and an outdoor fan. On the otherhand, each of the indoor units (30) is configured to be mounted on theceiling of an associated one of multiple different rooms, and includes acasing that houses devices such as an indoor heat exchanger and anindoor fan.

The refrigerant circuit (40) connecting the outdoor unit (20) and theindoor units (30) is configured by connecting the compressor and otherdevices together with a refrigerant pipe (41). The refrigerant pipe (41)includes a liquid pipe through which a liquid refrigerant flows, and agas pipe through which a gaseous refrigerant flows, and is composed of aplurality of parts (42). Examples of the parts (42) include straightpipes, elbows, branched pipes, and headers.

In particular, the refrigerant pipe (41) includes factory-assembledparts and site-assembled parts. Most of the refrigerant pipe (41) iscomprised of the factory-assembled parts. The factory-assembled partsinclude a pipe unit (50), which is one of the parts (42), and thesite-assembled parts include the outdoor unit (20), the indoor units(30), and couplings (43).

The pipe unit (50) is one of the parts (42), and includes, as shown inFIGS. 2-5, a pipe body (53) including a liquid pipe (51) and a gas pipe(52), and a heat insulator (54) covering the outside of the pipe body(53).

The first pipe unit (50) shown in FIGS. 2-4 is implemented as a branchpipe unit. Each of the liquid pipe (51) and the gas pipe (52) of thefirst pipe unit (50) includes a branch coupling (55) and extension pipes(56) connected to the branch coupling (55). The branch coupling (55)includes a bifurcated branch pipe (55 a) and short pipes (55 b)connected to the bifurcated branch pipe (55 a).

One end of each of the short pipes (55 b) is connected to the branchpipe (55 a) by brazing. The other end of each of the short pipes (55 b)forms a large-diameter connector (55 c), to which the extension pipe(56) is connected by brazing. The extension pipe (56) has its length anddegree of bending determined by the planning step to be described later.

The heat insulator (54) is provided for each of the liquid pipe (51) andthe gas pipe (52) to coat the liquid pipe (51) and the gas pipe (52)entirely outside.

The liquid pipe (51) and the gas pipe (52) coated with the heatinsulator (54) are fixed together with a tape (57) or any other fixingmember to form the pipe body (53). An end of the pipe unit (50) ismarked with a number indicating a connection position determined in theplanning step. The tape (57) may be implemented as a colored tapeindicating the connection position.

The second pipe unit (50) shown in FIG. 5 is implemented as a bent unit.This pipe unit (50) also includes a pipe body (53) and a heat insulator(54) covering the outside of the pipe body (53). A colored tape (57)indicating the connection position is wound around each end of the heatinsulator (54) of the pipe unit (50). The pipe unit (50) is marked witha number indicating the connection position.

Some coupling (43), which is one of the parts (42), may be implementedas a reducing pipe coupling connecting a large-diameter pipe and asmall-diameter pipe together as shown in FIG. 6. The reducing pipecoupling (43) includes a fitting coupling (43 a) and a reducing pipe (43b) which form integral parts of a single piece. The fitting coupling (43a) allows for connection without using fire, and has one end configuredto be connectable to a large-diameter pipe, and the other end to whichone end of the reducing pipe (43 b) as a small-diameter pipe isconnected. The other end of the reducing pipe (43 b) includes a flaredportion (43 c) and provided with a nut (43 d) as a fastening member. Theflared portion (43 c) of the reducing pipe is configured to beflare-connected to another refrigerant pipe (41).

As shown in FIGS. 7-9, the refrigerant pipe (41) is attached to anattachment position such as the ceiling of the building with asuspending band (60). The suspending band (60) includes a band body (61)which is a general-purpose band, a band coupling (62), and an elasticmember (63).

The band body (61) is in the shape of a thin strip, and is provided witha plurality of attachment holes (64) which are arranged at regularintervals in the longitudinal direction of the band body. The band body(61) is configured to be bendable to hold the pipe unit (50), forexample, and is suitably cut and set to have a predetermined lengthaccording to the diameter of the refrigerant pipe (41).

The band coupling (62) includes an interconnecting member (65) mountedon a suspending metal fitting attached to the attachment position suchas the ceiling, and a fastening member (66) including a bolt and a nutfor fastening both ends of the band body (61) to the interconnectingmember (65). Specifically, the fastening member (66) is configured tofasten both of the ends of the band body (61) that is wound around therefrigerant pipe (41).

The elastic member (63) has the shape of a cylinder, in which the bandbody (61) is inserted. With the band body (61) holding the refrigerantpipe (41), the elastic member (63) is located between the heat insulatorand the band body (61) to protect the heat insulator (41 a) of therefrigerant pipe (41).

—Method for Installing the Air Conditioner (10)—

An installation procedure, which is a method for installing the airconditioner (10), will be described below. The installation methodincludes a method for conducting a gastight test.

First, the installation of the air conditioner (10) begins by receivingan architectural drawing after accepting an order of installation workas shown in FIG. 10. For example, the installation begins by receiving adesign drawing of the building (11).

The installation of the air conditioner (10) includes a planning step(M1), a part fabrication step (M2), and an installation step (M3). Theplanning step (M1) includes a design drawing receiving step (M11), apiping drawing preparation step (M13), and a determination step (M14) asshown in FIG. 11.

In the planning step (M1), a piping drawing is prepared based on thedesign drawing of the building (11) in which the air conditioner (10)will be installed, and factory-assembled parts and site-assembled partsof the refrigerant circuit (40) are determined.

As shown in FIG. 11, in performing the planning step (M1), the flowstarts with the design drawing receiving step (M11) in which the designdrawing is received, and then may proceed to the piping drawingpreparation step (M13) after an on-site survey step (M12).Alternatively, the piping drawing preparation step (M13) may beperformed while obtaining information about the site concurrently.

Specifically, in the case of renewal work, the building (11) alreadyexists. Thus, survey of the building (11) is carried out to check theactual structure of the building (11) such as a beam structure. When thesite survey step (M12) is finished, the flow will proceed to the pipingdrawing preparation step (M13) to prepare the piping drawing based onthe actual structure of the building (11).

In constructing a new building, on the other hand, the survey of thebuilding (11) is impossible. Thus, when the design drawing is received,the piping drawing preparation step (M13) is performed while obtaininginformation about the site as the construction progresses to prepare thepiping diagram with the progress of the construction of the building(11).

Specifically, the design drawing may be a plan view of each floor of thebuilding (11) which shows lines indicating the piping of the airconditioner as shown in FIG. 12, for example. The design drawing showsunit marks (U1) indicating the indoor units (30) and line marks (L1)indicating the refrigerant pipes.

On the other hand, as shown in FIG. 13, the piping drawing is a detaileddrawing showing a piping system in which combined are part marks (P1-P8)corresponding to the parts (42) determined as the factory-assembledparts based on the design drawing and the results of the on-site surveyand other data. Specifically, the first to fifth part marks (P1-P5)indicate the parts (42) obtained by bending or curving the straightpipes, with their dimensions such as lengths (not shown). The sixth andseventh part marks (P6, P7) indicate the parts (42) obtained byconnecting the extension pipes (56) to the branch coupling (55), withtheir dimensions such as lengths (not shown). The sixth part mark (P6)indicates, for example, the pipe unit (50) shown in FIGS. 2-4. Theeighth part marking (P8) indicates the part (42) serving as a riserpipe, with its dimension such as a length (not shown).

Subsequent to the piping drawing preparation step (M13), the flowproceeds to the determination step (M14) to distinguish the plurality ofparts (42) by color-coding, for example. Specifically, the refrigerantpipe (41) of the refrigerant circuit (40) is comprised of the parts (42)such as the straight pipes and the pipe units (50). Thus, those parts(42) are given distinguishing identifications in accordance with theirpositions to which they are attached.

For example, as shown in FIGS. 4 and 5, the pipe unit (50) is providedwith the distinguishing identifications such as the tapes (57) which arecolored in, e.g., red, and wound around both ends of the pipe unit.Thus, an instruction indicating installation positions of thecolor-coded parts (42) is prepared in the determination step (M14).Specifically, the installation positions of the parts (42) are providedin a written form such that workers in charge of the installation canunderstand the installation positions of the parts (42). For example,the instruction specifies the colors and numbers given to both ends ofthe pipe unit (50) as shown in FIGS. 4 and 5.

Subsequent to the planning step (M1), the flow proceeds to the partfabrication step (M2) to fabricate, in the factory, the plurality ofparts (42) of the refrigerant circuit (40) corresponding to thefactory-assembled parts.

Specifically, the part fabrication step (M2) includes a fabrication step(M21), a gastight test step (M22), and a heat retention step (M23). Inthe fabrication step (M21), the parts (42) are fabricated, and thedistinguishing identifications indicating their installation positionsare given to the parts by color cording and numbering, for example,based on the piping drawing. Specifically, the pipe unit (50), which isone of the parts (42), is fabricated. For example, in the pipe unit (50)as the branch pipe unit, the short pipe (55 b) and the coupling (56) areconnected together by brazing to fabricate the liquid pipe (51) and thegas pipe (52). That is, the pipe unit (50) is fabricated in the factory,and the brazing process using fire is performed there.

Subsequent to the fabrication step (M21), the gastight test step (M22)is performed. For example, when the pipe body (53) is fabricated, agastight test is performed by blowing a nitrogen gas before covering thepipe body (53) with the heat insulator (54).

If the gastight test step reveals that the parts (42) are gastight, theflow proceeds to the heat retention step (M23) to provide each of theparts (42) with the heat insulator (54). For example, in the fabricationof the pipe unit (50), the liquid pipe (51) and the gas pipe (52) areeach covered with the heat insulator (54), and then the liquid and gaspipes (51, 52) covered with the heat insulator (54) are fixed togetherto finish the fabrication of the pipe unit (50). A fitting coupling (43)is attached to one end of the pipe unit (50)

The liquid pipe (51) and the gas pipe (52) of the pipe unit (50) arefixed together with the colored tape (57) indicating the installationposition, and the pipe unit (50) is numbered.

The lengths of those parts (42) that are the factory-assembled parts areset to be shorter than 4 m. Specifically, even the straight pipe parts(42) have their length set to be shorter than 4 m. In most cases, ageneral elevator has an opening (a width) of 2150 mm, a depth of 1600mm, a height of 2300 mm, and a diagonal length of 3467 mm. Thus, thelengths of each of those parts (42) is set to be shorter than 4 m suchthat the workers can take the elevator to carry the parts. Conversely,if the length of any of those parts (42) were 4 m or more, the workerswould have to go up the stairs to carry that part (42).

Subsequent to the part fabrication step (M2), the flow proceeds to theinstallation step (M3) to install the plurality of parts (42) fabricatedin the part fabrication step (M2) and the plurality of devices of therefrigerant circuit (40) corresponding to the site-assembled partsdetermined in the planning step (M1) (namely, the pipe unit (50), theoutdoor unit (20), and the indoor unit (30)) in the building (11).

Specifically, the installation step begins with an indoor deviceinstallation step (M31). The indoor units (30) as the indoor devices aresuspended such that the indoor units (30) are installed on the ceilingof those rooms. Then, the flow proceeds from the indoor deviceinstallation step (M31) to a piping step (M32) to attach vertical pipesas the straight pipes, for example.

In this piping step (M32), the pipe unit (50) and the straight pipesfabricated in the factory are connected together. In this step, the pipeunit (50) and every one of the straight pipes are connected together viathe fitting couplings (43), i.e., a brazing process or any other workusing fire is not performed. The refrigerant pipe (41) is mounted ontothe ceiling with the suspending band (60).

When the piping step (M32) is finished, the flow proceeds to an outdoordevice installation step (M33) to install the outdoor unit (20) as theoutdoor device. Then, the flow proceeds from the outdoor deviceinstallation step (M33) to a piping step (M34) to arrange pipes aroundthe outdoor device. Also in this step, the fitting couplings (43) areused to connect every pair of pipes, i.e., a brazing process or anyother work using fire is not performed.

When the piping step (M34) is finished, the flow proceeds to thegastight test step (M35) to perform a gastight test on the refrigerantcircuit (40) by blowing a nitrogen gas. Specifically, the gastight testis performed to check whether there is any gas leakage from thecouplings (43) or not. This gastight test is performed on therefrigerant systems (1A, 1B, 1C) by dividing each of these systems intoa plurality of sections.

If the result of the gastight test reveals that the refrigerant circuit(40) is gastight, the flow proceeds to the heat retention step (M36) toapply the heat insulators (not shown) to the straight pipes and othermembers. Thus, the installation of the pipes is completed.

Advantages of Embodiment

As can be seen from the forgoing description, according to the presentembodiment, the factory-assembled parts and the site-assembled parts ofthe refrigerant circuit (40) are determined in the planning step (M1),and the parts (42) of the refrigerant circuit (40) are fabricated in thefactory. This reduces the number of days required for the installationsignificantly. Specifically, the connecting work which has been carriedout on site is replaced with the work in the factory. This allowsworkers to get their work in a confined roof space and othertime-consuming jobs done much more easily, thereby reducing the numberof days required for the installation significantly.

Further, most parts of the refrigerant circuit (40) can be fabricated inthe factory. Thus, on-site work using fire can be reduced, which willcut down the number of fire accidents to happen on site. In addition,the heat insulation work can also be performed in the factory. Thisincreases the accuracy of the heat insulation work significantly, andprevents moisture condensation.

The piping drawing of the refrigerant circuit (40) is prepared based onthe design drawing. This increases the accuracy of the factory-assembledparts, and makes it possible to perform most of the piping work in thefactory. This ensures that the number of days required for theinstallation is significantly reduced even more reliably.

In particular, the piping drawing is prepared based on the on-sitesurvey. This increases the accuracy of the factory-assembled parts, andensures that the number of days required for the installation issignificantly reduced even more reliably.

The piping drawing gives the parts (42) the distinguishingidentifications. This clarifies the installation positions of the parts(42), simplifies the on-site installation, and ensures that the numberof days required for the installation is significantly reduced even morereliably.

Further, the instruction indicating the installation positions of theparts (42) given the distinguishing identifications is prepared. Thisallows for preventing incorrect connection of the parts and othererrors, thereby increasing the accuracy of the on-site installation.

The brazing process for connecting the parts (42) is performed only inthe factory, and the on-site pipe connection process is performed usingonly the fitting couplings (43). Thus, work using fire is restricted tothe factory, and no work using fire is performed on site any longer.This eliminates the occurrence of fire accidents on site. In addition,the brazing process performed in the factory reduces the number ofpositions where the fitting couplings (43) are used. This reduces thenumber of the expensive couplings (43) to use, which allows for cuttingdown the installation cost.

The pipe unit (50) fabricated in the factory is covered with the heatinsulator (54) in the factory. This reduces significantly the need forcovering the parts with the heat insulators (54) on site. As a result,the accuracy of the heat insulation work increases significantly,thereby preventing the moisture condensation with reliability. Inparticular, the moisture condensation may occur after a year or more haspassed since the installation was finished. The pipe unit (50) is veryeffective at preventing such moisture condensation.

The pipe unit (50) fabricated in the factory has already turned out tobe gastight by being subjected to a gastight test in the factory. Thissimplifies the gastight test to be performed on site. Specifically, evenif any leakage is found by the on-site gastight test, the leakage pointcan be spotted easily, because there is no leakage point in the pipeunit (50).

Further, use of the general-purpose band as the band body (61) of thesuspending band (60) makes the on-site installation very simple.

Further, with the plurality of (64) attachment holes cut through theband body (61), the refrigerant pipes (41) with multiple differentdiameters are held by the single band body (61).

The band coupling (62) mounted to the building (11) allows for both ofthe fastening of the band body (61) and the mounting of the band body(61) to the building (11) using a single member.

OTHER EMBODIMENTS

The above-described embodiment of the present invention may be modifiedin the following manner.

The three refrigerant systems (1A, 1B, 1C) of the air conditioner (10)may be replaced with only a single refrigerant system.

Naturally, the pipe unit (50) may be implemented as any of various typesof pipe elements such as headers.

The embodiments described above are merely illustrative ones in nature,and do not intend to limit the scope of the present invention orapplications or uses thereof.

INDUSTRIAL APPLICABILITY

As can be seen from the forgoing description, the present invention isuseful as air conditioners to be installed in buildings and otherconstructions.

DESCRIPTION OF REFERENCE CHARACTERS

-   -   10 Air conditioner    -   11 Building (construction)    -   20 Outdoor unit    -   30 Indoor unit    -   40 Refrigerant circuit    -   41 Refrigerant pipe    -   42 Part    -   50 Pipe unit    -   51 Liquid pipe    -   52 Gas pipe    -   53 Pipe body    -   54 Heat insulator

1. A pipe unit for an air conditioner, the pipe unit being provided fora refrigerant circuit (40) which performs a vapor compressionrefrigeration cycle by circulating a refrigerant, the pipe unitcomprising: a pipe body (53) having a liquid pipe (51) through which aliquid refrigerant for the refrigerant circuit (40) flows and a gas pipe(52) through which a gaseous refrigerant for the refrigerant circuit(40) flows; and a heat insulator (54) covering an outer periphery of thepipe body (53), wherein the liquid pipe (51) and the gas pipe (52) ofthe pipe body (53) are fixed together to form a single piece.
 2. Thepipe unit of claim 1, wherein the heat insulator (54) covers each of theliquid pipe (51) and the gas pipe (52) separately, and the liquid pipe(51) and the gas pipe (52), each of which is covered with the heatinsulator (54), are fixed together to form a single piece.